


Truth will out

by Pegship



Category: Castle
Genre: Angst with a Happy Ending, Canon-Typical Violence, Episode: s08e22 Crossfire, F/M, No Character Death, Truth Serum
Language: English
Status: Completed
Published: 2019-08-30
Updated: 2019-08-30
Packaged: 2020-08-14 16:28:59
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 4
Words: 4,952
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/20195257
Author URL: https://archiveofourown.org/users/Pegship/pseuds/Pegship
Summary: For a prompt on twitter: "What if Castle had ended up having an adverse reaction to the truth serum and collapsed down in that furnace room...in 8x22?" No character death, I promise.





	1. Chapter 1

Nothing in her life had ever felt so good as the arms of Richard Castle, wrapped around Kate so tightly that she could feel his every breath and every heartbeat. They clung together for a few moments, babbling out their love and relief to each other, then it was Castle who pulled back to look over at the inert form on the floor.

"Better secure him," said Kate. "Stand back, okay? I'm going to deactivate that damn magnet in the ceiling."

"Got it," said her partner, giving her arms a last squeeze before stepping over to stand against the wall.

Kate cuffed Mason Wood, then rummaged in his pockets until she found the remote and turned off the magnetic element in the ceiling. Looking over her shoulder, she saw that both her and Castle's guns had clattered to the cement floor; pocketing the remote, the keys, and other paraphernalia she found in Wood's pockets, she called out for Castle to get the fallen weaponry.

There was no reply or sound of movement besides her own. She rose from her knees to find the guns lying on the floor - along with her husband.

"Castle," she shouted, fear flooding her body. Even as she raced toward him, her brain was screaming at her: Aren't we done with this? When does it end?

He lay crumpled against the wall, half-sitting, half-lying down. His eyes were closed and his skin was pale. Kate felt frantically for a pulse, finding one at last in his neck, searching for some sign of injury.

He didn't seem to be bleeding, but when she pushed up his sleeves she saw needle marks in the crook of his elbow.

"What the hell did they do to you?" she snapped. She yanked out her phone and saw that there was no connection, then recalled the nature of the building she was in. No chance of calling anyone for help.

Kate was getting ready to haul Castle over her shoulder, maybe get him into Wood's vehicle, get him out of here and to a hospital, even as she knew that whatever they'd dosed him with was probably untraceable and untreatable. One thing at a time, she thought, and grabbed Castle's wrist and his belt, focusing on the search and rescue training she'd gone through long ago -

\- and her own wrist was gripped tightly in a slender hand, preventing her from further action.

"Don't move him," said the owner of the hand, quietly but firmly. "Sit him back up."

Kate looked into the eyes of a woman she had trusted more than once and said, "Back off, Rita. I don't know who's friend or foe any more."

"How's his pulse?" she asked Kate, who shook her head.

"Faint, but steady," she replied. "Who were you calling?"

"Backup," said Rita shortly. "Any idea what happened to Castle?"

"Needle marks, no sign of other injury," Kate reported. "I didn't even know he was here, until he burst out of that stairwell with a gun in his hand."

"Got the drop on Mason Wood?" said Rita.

"Not really," said a faint voice. Castle, his head lolling to one side, his mouth working to get words out.

"Castle - what happened? Were you poisoned? What did they give you?"

"Needle," he muttered. "Truth agent."

"I believe it," said Rita in answer to Kate's inquiring look. "But by their very nature they're not lethal. Easier to question a subject when he's alive."

"Twelve seconds." Castle's voice was fading. "Kill me in twelve…"

"Help me get him to Wood's car," said Kate. She couldn't just sit there waiting for further help.

"Where are you going to take him?" Rita demanded. "There's a battle going on upstairs; I guarantee you that the garage has been secured. Mine was the last car to get in before the safety doors slammed shut."

"This can't be it," Kate cried out in frustration. "We can't end like this, Castle. Castle!"

They'd won, hadn't they? Caught the Big Bad - escaped death, more than once - found their way back to each other. Now, any victory Kate could claim from this year of hell would be tainted and bitter, without Castle.

She cast her eyes frantically around the room and her gaze fell on the furnace. They'd both nearly ended up in there - reduced to ashes, or at least to a melted corpse like the one in the trunk -

The hand under hers stirred and her eyes snapped back to Castle, to see his fingers moving, his eyelashes fluttering.

He was struggling to lift his eyes to Kate; she leaned in and heard him hiss, "Story. Caleb."

"Caleb's dead, Castle," she told him. "It's over. Can you tell me what happened to you?"

His eyes closed again and he sighed out her name.

"Caleb Brown?" came the voice of Rita from over Kate's shoulder. "Is that who you're talking about?"

"We found his body, burned, in the trunk of a car," Kate told her. "DNA evidence, Caleb's briefcase, even a clue scratched out before he died."

But it doesn't matter, she thought bitterly. Dead or alive, it doesn't matter. Except that Castle had said the name, and by now she knew better than to dismiss his observations, however belated. What did Caleb have to do with Castle's current state? What story was Castle thinking of?

"Castle, who was it?" Rita grabbed Castle's other hand and took hold of his chin, tipping his face up. "Who was questioning you? Did he give you a name?"

His eyes were still closed as he managed to say, "Flynn."

Rita dashed for the garage exit, flinging ithe door open and disappearing into the darkness. Kate was ready to mutter, "Good riddance," but a moment later the woman reappeared with something in her hands.

"Give him this," she said, thrusting it at Kate.

"What is it?"

"Antidote," said Rita, ripping open the plastic package and pulling out a syringe.

"How do you know?"

"How's his pulse?" Rita countered. "Slowing down? He looks like he's losing circulation. Look at his fingertips - they're turning blue. We have to do something, Kate."

She was cracking the seal on a small bottle and filling the syringe with it; she handed it to Kate.

"Trust me," she said. "One more time. I haven't lied to you, Kate, and I'm not lying to you now."

"Who's Flynn?" Kate demanded.

"An amoral man who makes his living mixing chemicals to use on unwilling subjects," Rita told her. "I know him."

"Where did you get this? How do you know it'll work?"

"It's a broad spectrum treatment for the types of lethal poison Flynn prefers. I got it off of Caleb Brown when I tracked him to your strip club lair, earlier today. I'll tell you all about it after you save your husband's life."

Kate stared at the other woman.

"What do you have to lose, Kate?"

Kate took a deep breath and focused on the place where the other needle marks appeared, held Castle's arm still and injected the clear fluid into it. When she was done, she dropped the syringe on the floor and lifted his hand to her cheek, watching his face.

"He's cold," she whispered, laying a hand on the pulse point in his neck. "So cold. Castle, don't, don't leave me. Come on. We won, babe."


	2. Chapter 2

Castle felt a tiny, sharp pain in his arm.

"No," he tried to say. "Can't end like this. Kate, where's Kate?"

He had to tell her - he knew this feeling. Not just the pinprick, but the fog and dizziness and cotton-wool that was invading his brain. It reminded him of something - something Kate should know about -

"Kate."

Through the mental haze, he felt her hand on his face and heard her say again, "Don't leave me, Castle. Stay with me."

Even as the sound of her voice filled Castle with hope, he was still unable to move and his attempts to speak produced no result.

"His pulse is holding steady," said Rita - he recognized that voice now - from somewhere on Castle's left. He could barely feel her hand on his wrist.

"Tell me about Caleb Brown," said Kate's voice.

Yes! thought Castle. If only he could. He'd realized, once Flynn had told him about the incinerator, why leaving Caleb's body in the burnt-out car didn't fit the story. If this operation was run by LokSat, and LokSat wanted Caleb taken out, wouldn't it make more sense to consign his body to the incinerator? So convenient, so final.

Rita was replying to Kate.

"Castle disappeared, and so did you. We thought he might be headed for the precinct, but he never showed, and we had no idea at all that you were going to meet Mason Wood."

"We?"

"Vikram and I. Hayley got hold of me after Castle left the PI office, so I went over to the precinct. I never saw you leave - you're sneakier than I thought."

"I know where all the exits and cameras are," Kate said dismissively. "What then?"

Kate, Kate, Castle was fuming inwardly throughout this conversation. You said you'd stay there, where you were safe, and instead you run off after Wood without a word to anyone. That never, ever ends well.

Then again, he'd done something similar. But then again, at least he'd left word as to his destination. Now he was getting annoyed that his mind was clear enough to have this conversation with himself, but his body wouldn't cooperate enough for him to participate in the other conversation.

"I lurked around until Vikram reported to me that you were gone," said Rita. "I went over to the strip club and found Caleb Brown tossing the place, down to the woodwork, probably looking for clues as to how far your investigation had progressed. He wasn't expecting company."

She sounded justifiably smug.

"What did you do with him?" asked Kate.

"Rendered him inoperative, but alive. I knew about this facility from the old days, so thought I'd bring him along and dust off my in-house interrogation methods. He's out there in the garage, bound, gagged, and strapped down in the SUV I'm driving.

"No sooner did I get inside the garage than all hell broke loose," Rita finished up. "I didn't know about Flynn, or Mason Wood, but I figured if you two were missing and this place was locked down, it might have something to do with our target, so I burned rubber and parked next to the fastest way upstairs. And here you were."

"And this stuff you gave me, to inject him with?" Kate persisted.

"Like I said, a broad spectrum antidote. Standard issue; I recognized the code on the vial while I was rifling Caleb's belongings. It won't hurt him, but it might not help him, if Flynn has come up with something brand new in the neurotoxin line."

Neurotoxin, thought Kate, her mind racing. Something clicked.

"I've seen this happen before," she muttered. "Where have I - "

Something Flynn had said came to Castle's wandering mind. While waiting for his concoction to take effect, Flynn had told him what would happen if his methods proved ineffective.

"A bullet causes death more reliably than a substance which must be diffused throughout the body, but it's messy and too easy to trace. I prefer chemical agents - far less traceable and without all the noise and physical destruction."

Chemical agent, thought Castle. Toxin… why does that ring a bell?

Something clicked.

"Parker," he whispered. "Secretary Reed. The toxin."

"Brad Parker," said Kate. "The toxin he used on Bronson - on Mary Reed."

"What toxin?" Rita asked.

"I'll explain later," Kate replied. "After I save my husband's life. Castle!"

Kate laid her palm on Castle's head. He looked every bit as pale and limp as he had on the lawn outside Reed's house, where he'd collapsed as she'd chased down the man whose stolen toxin was killing him.

"Castle, can you hear me?" She tipped his chin up and carefully lifted his eyelid. "I need to know - is this how you felt when you were poisoned? In D.C.?"

His mouth fell open and his throat worked for a moment. At last he said, "Parker. Bronson. Stolen… chemical."

"If Flynn had that substance in his lab, the antidote had to be there too," Kate said to Rita. "The poison is very fast acting. It's a miracle it hasn't killed him yet. Do you know where the lab is?"

Before Rita could answer, they were interrupted by an unexpected sound - the sound of Kate's cell ringing. She snatched it off her belt and spoke into it.

"Beckett."

"Esposito here," said a brisk, familiar voice. "Your location, Captain?"

"Government building, corner of - "

"We tracked you," Esposito broke in. "Your signal disappeared when you entered the building, but Ryan and I were headed that way anyway. Thought we'd better check on you."

His tone was deliberately casual, but Kate knew him; he was angry that she'd slipped out of the precinct after promising not to - and ended up in this snake pit of an operation.

"I'm in the basement. Castle's here. He's - I think they put something in him, Javi. Is the building secure?"

"We're going floor by floor. Should be clear up to three, which is where we are. And we found our pyromaniac, by the way - once we fought our way in here and stopped whatever he was doing to Castle."

"Tell me what he was doing?"

"He had an IV in his arm - the suspect was about to activate it when Ryan shot the whole bag off the stand. Castle took off to find you and that's the last we saw of him. He was moving pretty fast…"

"Do you have that suspect in custody? Is he conscious?"

"He's right here," said Esposito. "Giving me a dirty look. Forget it, man - I've been glared at by meaner folk than you."

"Hold the phone up to his ear, Jav."

There was a shuffling sound, and Kate heard someone breathing heavily into the phone.

"Is this Flynn?"

A man's voice, strained and angry, said, "Yes."

"What did you give to Richard Castle?"

More breathing and the sound of teeth grinding. Then Kate heard Ryan say, "Castle left him hooked up to this stuff, I don't know what it is. Any idea?"

"Truth agent," Flynn managed to say.

"Oh, so you're under the influence of a truth drug?" Kate asked.

"Yes." Another growl.

"Answer my question, Flynn. Besides the truth agent, what did you give Richard Castle?"

"Nothing."

We don't have time for this interrogation, Kate thought furiously. She closed her eyes and cast her memory back - more than two years back! - and pictured the doctor at Walter Reed telling her about the substance that had nearly ended Castle.

"Tell me this," she said to Flynn. "Is there any amount of the antidote to this toxin in this building?" She named the toxin, as clearly as she could remember it, and held onto Castle's hand -

"Yes," said Flynn grudgingly.

"Tell Detectives Esposito and Ryan where to find it," she ordered. "Espo?"

Esposito came back on the line. "Here."

She told him what to do with the antidote once Flynn handed it over, then ended the call.

"What the hell is that stuff you just rattled off?" asked Rita.

"A classified biochemical substance that Castle was accidentally exposed to, back when I was with the AG's office," said Kate. "If I'm right about these symptoms, and if Flynn was telling the truth about the antidote - it means that someone has gotten hold of the toxin, and that Castle has been exposed to it, again."

"Brava," said a faint voice from the corner. Mason Wood. "Too late, though."

"We'll see," Kate snapped over her shoulder. "He's not dead. He's fighting it."

"He'll lose," Wood went on ruthlessly. "You of all people should know how fast that stuff works. Flynn was preparing to administer it when I saw him last, right before I came to meet you."

"Well, either Flynn waited too long, or there's something you don't know about the toxin," Kate replied. There were more puzzle pieces falling into place in her mind; if Wood and his minion had knowledge and possession of this substance, they had to have connections to the lab where it had been kept. A lab so secret that the AG's office wasn't even aware of its location or its contents until her team came across it while investigating something else.

The sound of someone barreling down the stairs made Kate and Rita reach for their sidearms, but it was a welcome arrival - Esposito with a couple of vials in one hand and his own weapon in the other. He pulled up short, took in the sight of the two women kneeling beside a prone Castle and the prisoner stirring in the corner, and dropped to a squat next to Kate.

"Here you go," he said. "This is the counteragent to the stuff Castle was about to get dosed with when we busted in. So says Mr. Flynn - if you're willing to take a chance on that truth drug he's supposedly under."

Kate was already tearing open the clean syringe Espo had brought with him and filling it with the contents of one of the vials.

"D'you think Castle really was exposed to that toxin, here in Flynn's lab?" Rita murmured. "Could it have been administered somewhere else? Or was it something different?"

"We'll find out soon enough," said Kate.


	3. Chapter 3

As Rita and Esposito conferred over what to charge Mason Wood with, Kate's mind was racing. If this didn't work, what next? No ordinary hospital would have knowledge of the drugs Flynn worked with, or how to treat their effects. Before LokSat came to her attention, she would have called her former team at the AG's office.

"Walter Reed," she said abruptly.

"Too far," said Rita, returning to her side. "We don't know how long he'll last like this."

"We can call them," said Kate. "Talk to someone who treated him there, last time. Even if they don't know the specifics, surely they can suggest some form of treatment."

"Can't get that kind of clearance over the phone." Rita chewed her lip, thinking. "Well, I can't. But I know someone who can."

She ducked out of the room again, back into the garage, presumably to contact the someone she mentioned. Without taking her eyes off Castle, Kate asked Esposito, "How come our phones started working all of a sudden?"

"You can thank Vikram for that," said her colleague, coming to stand nearby. "Whatever tech they use to scramble or block cell transmissions, he hacked in and disabled it."

"Where is he?"

"Back at the precinct. I told Karpowski to throw him in Holding if he tries to sneak away." He glared at Kate. "Setting a bad example there, Cap."

"I know," said Kate ruefully, "and I'm sorry, Espo. I just - I thought that if I went off on my own, no one else would be endangered. Look how that turned out."

"On the upside, Karpowski's been waiting for a chance to lock Vikram up and have her way with him," Esposito smirked.

Kate smiled for the first time in what felt like ages, then looked up as Rita came back into the room.

"Here," she said to Kate, handing her a cell phone. "His name is Streiten - he's a neurologist. That SHIELD fiasco - well, he's the very best, Kate. And he's worked with exotic chemicals like this."

Kate took the phone. "Dr. Streiten, this is Captain Kate Beckett of the NYPD."

"Rita told me the bare bones of your situation," said a mellow voice on the other end. "If it's the same substance used on Mr. Castle in 2013, that should be well out of his system by now. Should have only taken a week to test clear. Is the antidote having any effect?"

"He's not as blue as he was ten minutes ago," said Kate. "His pulse is steady. He's still unconscious and his skin is clammy."

"What else has he been given in the last two hours?"

"Some kind of truth serum," Kate reported. "I don't know what else."

"It's hard enough figuring this out over the phone," said Streiten apologetically. "I don't want to guess at what you're treating. Does anyone know what the serum was?"

"Only one person - "

On the heels of Streiten's question came Kevin Ryan, gripping the arm of Flynn, who was cuffed, bandaged, and looking fairly dazed. Ryan hauled the man over to stand next to Rita and said, "This the guy?"

"Flynn - " came a faint voice from the corner. Esposito's head snapped around and he strode over to Mason Wood's prone body.

"Shut up," he growled. "Rita? I don't trust these two in the same room."

"We got this," said Rita to Kate. She and Esposito wrestled Wood to his feet and took him out into the garage.

"Doctor," said Kate into the phone, "I have someone here who administered the truth serum to Castle, who may have given him the toxin as well."

She put the phone on speaker and video call, and the screen lit up on the face of an older black man with iron-gray hair. When Streiten saw the man Ryan was holding, his expression went coldly angry.

"What did you give him, Flynn?" he demanded.

Flynn swayed a little, then answered with a chemical name. Streiten shook his head.

"That's what he'd give him to subdue him, not a truth serum or toxin," he told Kate. "What else, Flynn?"

Flynn's jaw was clenched; clearly he was trying not to answer. Into Kate's mind flashed an image of Castle trying to resist questioning, as he must have only too recently. She shoved it away in time to hear Flynn mutter another chemical formula, and the sound of the doctor typing.

"It isn't a toxin," he said at last. "What else was he given, Flynn?"

"Nothing," Flynn answered. "This man shot me in the hand before I could carry out my orders."

Ryan did not look as though he regretted his actions.

"It's a variation on a fairly new chemical agent," said Streiten. "I'm still privy to much of the research going on at - well, anyway, I have the antidote formula from Rita, and even though the toxin wasn't administered, I see that the antidote formula should also have a dampening effect on the truth serum."

"So if the truth agent isn't lethal, and the antidote isn't either - " Kate gazed at the man on the screen, who looked troubled. "What can we do?"

"Make him comfortable," said an unexpected voice from beside Ryan. Flynn was looking at Kate with an oddly serene expression. "Monitor him."

"What should we be watching for?" Streiten asked immediately.

"Blood pressure drop, sweating, hallucinations," Flynn replied. He didn't seem to be fighting the questions now - rather, he seemed interested by the medical problem. "Possibly seizures."

"How long will this condition last?"

"It varies," Flynn shrugged. "I've never had a subject his age and size before. I don't know his metabolism."

"What happened to the other subjects? As a result of the serum, I mean," Kate added hastily.

"Some of them recovered on their own, the most recent of them. It took some time to construct an agent that wouldn't kill, at least, not quickly."

That statement was delivered so calmly that Ryan and Kate stared at each other, appalled, for a moment. Streiten cleared his throat and asked, "The agent you gave this man - was it the lethal version, or non-lethal?"

"Non-lethal," said Flynn. "We didn't know how long we would need him, so I was to administer the lethal formula as a separate dose."

Ryan looked relieved. "Whew, I guess stopping that dose was the right move."

Flynn actually glared at him. "You shot me."

"Winged you. You'll recover. Speaking of which, do you still need him?" Ryan asked Kate, nodding at Flynn.

"I don't think so," she replied. Castle looked better, almost as though he'd fallen asleep. Or been knocked unconscious - which she'd seen at least once before.

Rita came back through the door to report. "Backup's arrived. Wood and Brown have been transferred to separate vehicles - I want to get them out of here before the folks upstairs grab 'em. Taking them to your precinct, I presume?"

"Thank you," said Kate fervently. At least if the NYPD had custody, she knew her suspects wouldn't disappear. "Dr. Streiten, thank you so much."

"You're welcome - I'm glad I could at least advise you."

"You knew the right questions to ask," she told him. "If you're ever in New York - "

He smiled a little. "For all you know I already am."

He signed off. Kate looked up to find that Ryan had hustled Flynn out to the garage and Rita was kneeling beside Castle once more.

"He looks better," she said. "Medical is here - they can take him to whatever medical facility you want."

"I'm going with him," said Kate.

"They need you upstairs, Cap," said Esposito, who had just come in. "Mop-up, mostly. Castle's in good hands."

"I'm sure he is," Kate said. "But I'm not leaving him, not this time." Maybe not ever, she thought. Getting separated, whether physically or emotionally, had never ended well for either of them. She was done with the Lone Ranger method. "Sorry, Espo. I'm making my choice - him, over the job."

"Beckett…" Esposito's reply trailed off when he saw her expression, then he gave a rueful little smile. "Houlihan's ranking officer, then; he's still in the lab, along with a couple of CIA suits. I'll go find him."

He leaned down to pat his captain on the back. "Do what you gotta do, boss."

He left the room and the EMTs came in with a gurney. Rita spent a few minutes talking to one of them while the other helped Kate get her husband onto the rig and strapped down. Once they were ready to go, Rita came over and hugged Kate briefly.

"Here's Streiten's number," she said. "I recorded the phone call as well - I don't trust myself to recall those formulas - I'll send the recording to your cell."

"Will you come see him?" asked Kate.

Rita knew she didn't mean Streiten. "Can't promise," she said. "I'll keep my ear to the ground, though. Anybody tries to cause trouble, I'll bring the hammer down on 'em."

She looked down at the man on the gurney and added, "Unless he's the one causing the trouble, in which case, you're on your own."


	4. Chapter 4

Kate Beckett was disciplined and put on probation for her various infractions of federal and state law during the LokSat case. The NYPD didn't want to lose her entirely, and she was told the only reason she was given another chance was the outstanding nature of her previous service.

The psych evaluation was the last step in the probationary process, and the eighth session she'd had with Dr. Burke since the showdown in the CIA building. Of course, she could tell Burke very little about that incident, as it was classified - but she could and did talk about her relationship with her team, and with her husband.

"I made some bad choices," she admitted over the course of their meetings. "Castle was there for me, through everything, even once he found out how far I'd gone to push him away. He told me, when he found out what I'd been up to, that - that I was broken. That I needed my obsession."

Castle had been right, she thought. The demon she thought was gone was only lurking, and the moment she heard its siren song she had seized on it as a familiar weapon. For so long she had been the point man in her own battles, that she'd only belatedly recalled the formidable force that was her lover - and just how valuable he was in any skirmish.

She would never have survived this long without him. Certainly not against such determined, amoral enemies. Whatever came now, she would not face it without Rick beside her.

Now Carter Burke sat across from her, smiling his enigmatic smile, and said, "I plan to sign off on your psych eval, Kate, so once you pass your firearms requalification, you'll be cleared for reinstatement. If that's what you want."

Kate smiled back. He knew her well enough by now to guess that going forward with the NYPD was not the only option she was considering. She thanked him and they shook hands, and he wished her success in whatever path she chose.

Rick was loitering on the sidewalk when Kate came out of the building; he caught her up in his arms and swung her around in a hug.

"So?" he inquired once she was back on the ground. "All clear, I presume?"

"All clear," she told him. "You'd know right away if it wasn't. You read me too well, Castle."

"Not well enough to guess the other thing." He took her hand as they turned to walk down the street. "I'm never going to live that down. My Spidey sense must be on the fritz."

"Don't be too hard on yourself," she grinned. "You're not the first man to be blindsided with the news his wife is pregnant."

"If you want to know the truth, I'm still kind of knocked out, twenty-four hours later." He looked down at her hopefully. "I think I might need some ice cream to help my recovery. You might need some, too."

Kate gave him a nudge and a smile and said, "Precinct first. Ice cream after."

Her business with the NYPD would not take long.


End file.
